Chronology of trace elements and radionuclides using sediment cores in Golden Horn Estuary, Sea of Marmara

Trace elements and radionuclides are substantial pollutants in marine environment since they are non-biodegradable and can be harmful even in minute concentrations. The Golden Horn estuary, where is an inlet of Bosphorus and two creeks, has been seriously polluted by untreated municipal and industrial dischargers for several decades. Since 1998, a large restoration and rehabilitation efforts have been undertaken in the estuary to mitigate the pollution. In the present study, four sediment cores were taken from the Golden Horn estuary to assess the historical accumulation of trace elements and radionuclides. Radiometric dating was implemented by 210Pb and 137Cs radionuclides and CRS model. Sedimentation rates were calculated in the range of 0.92–0.97 cm yr−1 in the estuary. The distribution of radionuclides (40K, 226Ra, and 228Ra) indicated some slight variations which ascribes to the geological characteristics of sediment along the cores. The concentrations of the anthropogenic elements were relatively higher in the intensive industrialization period. Their concentrations reduced in the latest 15–20 years thanks to the large-scale rehabilitation project in the estuary. The pollution indices, namely EF, Igeo, CF, and PLI showed that the concentrations of Cd, Cr, Cu, Pb, Sb, and Sn were above the world averages. Our results provide an insight on the long-term accumulation trends of trace element in the Golden Horn, which revealed that the estuary remains moderately polluted. We suggest that preventive countermeasures are much more important than post pollution remediation in the case of metallic pollution in the estuaries. © 2022 Elsevier Lt

Assessment of Po-210 and Pb-210 by moss biomonitoring technique in Thrace region of Turkey

This study presents the first data of Po-210 and Pb-210 activity concentrations using moss species Hypnum cupressiforme from Thrace region, the northwestern part of Turkey. The moss samples were systematically collected from 40 locations in the study area. The average with standard deviation and range of Po-210 and Pb-210 activity concentrations were found to be 409 +/- 128, 188-777 and 494 +/- 183, 178-852 Bq kg(-1) at dry weight, respectively. Comparatively higher radionuclide activities were found in the northeastern Thrace, probably due to Rn-222 daughters attached to aerosols through high rainfall in this part of the region. A significant positive correlation was found between Po-210 and Pb-210, which shows that their source and/or bioaccumulation behavior are similar. The average and range of Po-210/Pb-210 ratio were calculated to be 0.89 and 0.47-2.67, respectively. Those levels were calculated to be mostly lower than unity that addressed the abundance of Pb-210, probably due to predominantly inorganic particles through atmospheric deposition

Temporal changes of atmospheric deposition of major and trace elements in European Turkey, Thrace region

In the present study, the actual levels and temporal changes of 34 major and trace elements were examined in 44 moss samples Hypnum cuppressiforme collected across Thrace region. The concentrations of Cr, Cu, Fe, Ni, Sb, V, and Zn were found to be higher than the local background in the vicinity of corlu, one of the most industrialized cities in Thrace region. The concentrations of Fe and Pb exceeded the local background level in the locations close to the Istanbul Airport construction. The highest concentrations of As, Cd, and Sb were found in Istanbul metropolitan area most probably due to intense traffic and industrial activities. Enrichment factors were calculated between 1.4 and 15.8, and Cd is the highest value among the investigated elements. The median levels of some significant anthropogenic elements including As, Cd, Cu, Pb, and Sb in moss samples remained unchanged over sixteen years, suggesting that the actions were insufficient to reduce the release of these elements